Extending the deck

Extending the deck

Auto-markingPencil and paperOnline interactive
Overview
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Further Resources
This task is about working out area.

Question 1Change answer

The Jacobs have a diamond-shaped deck. Its measurements are shown in Diagram 1.

Diamond-deck-1.png

a)  What is the total area of the deck?  m2

Question 1Change answer

They decide to extend the deck on one side. This is shown by the thick dotted lines () in Diagram 2.

Diamond-deck-2.png

b)  What is the total area of the deck now?  m2
Task administration: 
This task can be completed with pencil and paper or online (with auto marking displayed to students).
Level:
5
Description of task: 
Students calculate the total area of a deck and a deck with an extension.
Learning Progression Frameworks
This resource can provide evidence of learning associated with within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
   

Y10 (12/1997)

a) 24 m2 moderate
b) 36 m2 moderate
Diagnostic and formative information: 
  Common errors Likely calculation Likely reason
a) 25 5 × 5 Assumes area of rhombus = area of square.
a) 720 3 × 3 × 4 × 4 × 5 Multiplies all dimensions to get area.
a)
b)
20
24
5 × 4
5 × 2 + 7 × 2
Confuses area and perimeter.
a)
b)
34
48
5 × 4 + 3 + 4 + 3 + 4
34 + 2 × 7
Confuses area and total length of all lines.